1. Field of the invention
The present invention relates to a torch-angle setting device which is advantageously used together with a cutting device for carrying out the groove-angle Cutting of material being cut by gas cutting torch, plasma cutting torch or laser cutting torch.
2. Description of the Prior Art
In a field such as shipbuilding, bridge construction or building, there are many cases where a plurality of steel plates, each having a given size, are welded to each other in order to form a construction. When steel plates are welded to each other, the thicker the thickness of steel plates becomes, the more difficult it is to expect weld penetration uniform in the direction of thickness. Therefore, the groove angle is generally formed.
In particular, there are parts having an outer periphery formed of curved line in special parts used in shipbuilding, or bridge construction. In this case, it is needed to cut material being cut into a design having the periphery formed of a curved line, and, at the same time, to carry out groove-angle cutting. Further, even in other parts, there are cases where groove angle is needed to be prepared on a design having a curved or straight periphery.
The structure of a cutter for the groove-angle cutting of material being cut is explained hereinafter. When cutting material such as steel plates, a gas cutting torch, plasma cutting torch, or a laser cutting torch is selectively used in a general way. When a groove-angle cutting is carried out, a torch is inclined at the cutting angle, and this cutting angle is maintained until the objective groove-angle cutting is finished. Therefore, when material being cut is cut with a groove angle in a curved line, a torch-angle setting device is formed in such a manner that a torch can be turned so that the direction of the torch coincides with the curved line.
Further, a position as a standard of control in the case where cutting is made, is the intersection of the extension of line of a torch and material being cut, wherein a locus of the intersection coincides with an objective design. Accordingly, it is not a problem of utmost importance whether the intersection of the extension of the line of a torch and material being cut coincides with the intersection of the extension of the line of a turning shaft and material being cut, as a reference when turning the torch. Therefore, when a torch in which the two intersections do not coincide with each other, an offset system machining head is formed, and as a torch in which the two intersections coincide with each other, a zero offset system machining head is formed, and programs corresponding to the respective machining heads are provided.
As mechanisms for setting torch-angle, various mechanisms have been provided. However, when using a gas cutting torch or plasma cutting torch, the mechanism for setting the torch-angle is generally formed in such a manner that a torch can be set at a desired angle by mounting a torch holder for holding a torch on a carriage which moves along a fan-shaped guide, and moving the carriage by means of a motor. In this mechanism, the turning of a torch is carried out by turning the fan-shaped guide, wherein a zero offset system machining head can be realized by keeping the fan-shaped guide away from the turning shaft, and by aligning the torch with the turning shaft.
Further, in the case of a laser cutting torch, the torch is provided with a mechanism for inclining the torch at an objective inclined angle, and with a mechanism for aligning straight-passing laser beam with an inclined angle of the torch while reflecting the laser beam.
In case of using a laser cutting torch as a torch and setting the torch-angle thereby, there has been a problem when forming a zero offset system machining head, the structure thereof is complicated and large-scaled, because the mechanism for a reflecting laser beam is needed. Therefore, an offset system machining head has been generally formed. However, in this case, there is a problem in that the machining head lacks smoothness when turning a torch along a curved line in the objective design, so that a notch (groove, concave) is formed in a cut surface.